From entering the Martian atmosphere and its dust storms to contact with the ground, everything was indeed preprogrammed.

And all the delicate phases of entering the Martian atmosphere took place according to plan.

“With Mars, nothing is ever acquired. Mars is difficult, “said Thomas Zurbuchen, head of NASA’s scientific directorate, the US space agency, which approved the nearly $ 1 billion mission to study the bowels of the red planet.

The last aircraft to land on Mars is the NASA Curiosity vehicle, the only one still active on this planet near our Earth. Only the United States managed to put robots there. The USSR crashed several landers, just like the Europeans, just recently in 2016.

The mere friction of the atmosphere quickly raised the temperature to 1,500 ° C but the machine was well protected from a reinforced heat shield.

The aircraft was moving at about 20,000 km / h, three to four times faster than a rifle bullet, aiming for a 10 km by 24 km rectangle. Compared to the 480 million km of his journey, “it’s like scoring a goal at 130,000 km away,” said NASA.

Four minutes and a hundred kilometers lower, a parachute opened automatically, braking brutally the descent. Then, once dropped the heat shield, the undercarriage deployed his three legs and the parachute broke off.

To stop his free fall, the probe quickly ignited its 12 retrofuses that slowed down to about 8 km / h the descent of the machine, which now weighs more than 365 kg.

At 19:54 GMT, nearly seven minutes after his first contact with the atmosphere, InSight was finally able to “amarsir”.

The belly of Mars

Throughout this time, nicknamed “the seven minutes of terror” by some, and that actually lasted six and a half minutes, nothing or anyone could help InSight to correct a trajectory or remedy a failure.

“We’ve done everything we can to make sure the mission is a success, but you never know what’s going to happen,” said Tom Hoffman, head of InSight’s project for NASA, acknowledging “I did not sleep very well.” ” recently.

“The atmosphere of Mars is treacherous, it is very tenuous, it is not homogeneous, that’s why it’s complicated,” told AFP the president of the French space agency, Jean- Yves Le Gall.

The boss of the Cnes had reasons to be anxious: InSight’s main goal is to put on the Martian surface an instrument designed by his agency: the seismometer SEIS.

Hundreds of American and European engineers and scientists who have been working on InSight for seven years have had to wait for long minutes for the first signal sent by the LG, proof that it is intact and well on its three feet.

Last crucial step: the very slow deployment of the two solar panels of the machine that will supply its instruments with energy.

Because a busy work program is waiting for the probe.

She must listen to the inside of Mars to try to understand the thickness and composition of the soil, from the crust to the core, which is unknown if it is liquid or solid. Knowledge that will better understand the formation of the planet, billions of years ago, and therefore the Earth, the only rocky planet we have really studied the interior so far.

The seismometer of French design will listen to the most minute vibrations of the ground, caused mainly by the shock waves of meteorites and earthquakes. These waves will draw an inner map of the planet.

Another remarkable instrument, German one: HP3 looks like a mole connected by a leash to the undercarriage and will dig 3 to 5 meters deep below the surface of Mars to take its temperature.